5 - Waterless natural dyeing to make it sustainable

Abstract

Strict environmental laws and regulations have led to the use of natural dyes in textile dyeing a major boost worldwide. As the use of water in textile industry is immense, the need of alternative technology and materials which can replace water as major constituents in dye house is now new aim to be accomplished. Waterless dyeing is not far fetching as new methods seem to be present on research horizon and ready to be standardized. The application of natural dyes in waterless dyeing can prove to be a new landmark in dyeing industry which can bring a real boost in cutting down carbon footprint of whole dyeing process along with ecologically safe procedures. This can lead to cheap products, lesser chemical use and their management, and, above all, zero waste water generation and no effluent treatment requirement. Recently research of supercritical fluids as reaction and solvent medium has been revived, with protocols to fulfill environmental regulations using efficient processing and separation techniques. Carbon dioxide-assisted supercritical fluid-mediated technology has confirmed to prove a leading process as it has emerged as the most preferred supercritical fluid. This along with natural dye sources can make natural dyeing a major player in waterless dyeing domain. The use of natural dyes along with CO2 supercritical fluid needs to be established on pilot-based studies before adopting it on industrial scale. As carbon dioxide is the most investigated and used supercritical fluid which is characterized by exceptional physical-chemical properties, generally been used in extraction processes, might have potential to give delighted results in dyeing as well. This can lead to an environment-friendly process for an important step in textile finishing.